Figure 2-1. Station evolution. The chart above summarizes the development of the Soviet/Russian space stations and derivatives. Light gray arrows trace the evolution of space stations and satellites derived from space station hardware. Dark gray arrows trace the influence of concepts on later flown hardware. The stippled arrow leads from the Soyuz Programs chart (figure 1-1). Solid black arrows indicate modules joined to Mir, while dashed black arrows stand for modules to be added to Mir in the near future. These arrows lead from the Station Modules and chart (figure 3-1).